Soil sampler apparatus and method

ABSTRACT

An apparatus removes soil samples at intervals over a field of interest. The apparatus comprises a sampling assembly ( 60 ) that rotates on a track ( 32 ) riding on a plurality of idler wheels ( 29, 31 ). A probe ( 66 ) extends and retracts under the action of a scissored frame assembly ( 70 ), mechanically manipulated by passage of the scissored frame assembly ( 70 ) along a guide assembly ( 108 ). The probe ( 66 ) is extended into the ground and retracted on each revolution. An ejector ( 68 ) pushes soil from the probe ( 66 ) as it passes over a hopper ( 88 ) to retain the cores. The cores are pneumatically transferred from the hopper ( 88 ) to a plurality of sample collection containers ( 126 ). An electronic control system uses GPS location information to deposit collected cores in the appropriate container ( 126 ) based upon the current location of the apparatus in the field of interest.

This application claims the benefit of U.S. provisional patentapplication No. 60/454,460, filed Mar. 13, 2003 in the name of James D.Burton and entitled “Soil Sampler.” The disclosure of such provisionalapplication is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to soil sampling devices and methods, andin particular to soil sampling devices that periodically andautomatically take soil samples over an area of interest, and relatedmethods.

BACKGROUND ART

In order to optimize the production capacity of any agricultural land,the grower must provide in each plot of soil the amount of fertilizersand other nutrients and additives that will render each plot ideal forthe crop that is to be sewn and harvested. The grower cannot know howmuch fertilizer or other additives should be placed at a plot of soil,however, without knowing the current level of nutrients and importantminerals that are already present in each plot. The quantity of thesevarious materials present will vary greatly depending upon the soiltype, the history of crops grown, and additives that have beenpreviously applied to the field. It is thus a common practice forgrowers to periodically remove soil samples from various regions ontheir agricultural lands, which are then analyzed to determine the levelof various important nutrients and minerals that they contain.

Soil sampling has historically been a process performed by hand. Varioushand tools have been developed to somewhat ease the burden of this task,but any manual operation to perform soil sampling is necessary tiresomeand time-consuming because of the expanse of land that must be coveredwhen soil sampling is performed as part of a large-scale commercialfarming enterprise. Not only must a worker remove each sample, but thesample must then be transported back to a laboratory for analysis, andthe samples must be transported in such a manner that samples fromvarious plots are not mixed. Further, the samples must each be carefullylabeled, and the worker must keep careful track of his or her locationwhen each sample is removed. Because of the arduous nature of this task,growers typically take only one sample in a field of interest, or atmost a few samples across a field or area of interest and then averagethe results. The farmer will then apply fertilizers and other nutrientsto the soil as if the soil's level of nutrients were uniform across thefield, which is in fact not generally the case. The result is a poorapproximation of the optimal nutrient level for each plot of soil, sincesome plots will likely be under fertilized and others will be overfertilized. Under fertilized plots will produce poor yields, and overfertilized plots may both produce poorer than optimum yields and alsoresult in a waste of fertilizers. The wasted fertilizer not only is anadded expense for the grower, but also exacerbates environmental issuesthat may arise from the later run-off of the excessive fertilizer due torain or wind.

With the wide availability of global positioning system (GPS) satellitereceivers today, the use of GPS information in soil sampling is rapidlyincreasing. Currently it is believed that approximately 15% of totalfarm acreage in the United States (roughly 640 million acres) uses GPSinformation in conjunction with soil sampling efforts. It is expectedthat GPS usage will increase to encompass approximately 28% of totalfarm acreage by 2005. The use of GPS in conjunction with manual soilsampling, however, only provides modest improvements in accuracy andefficiency. Although the grower now has precise information about whereeach sample is taken, manual sampling procedures still require a workerto travel to each identified point in the field of interest, remove asample by hand, and then label and transport that sample for analysis.Thus it would be highly desirable to develop a soil sampling system thatwould periodically sample the soil across a field, while automaticallykeeping track of where samples were removed using GPS information, andautomatically separating the samples according to location for ease ofanalysis. Such a system would ideally allow the operator to simplydirect the sampling mechanism around the field in a regular pattern,while the mechanism performs sampling in a manner that is automatic andeffectively transparent to the operator.

The related art includes several attempts to develop soil samplingmechanisms that periodically sample soil over an area. U.S. Pat. No.3,224,512 to Alexander teaches a soil sampler that is mounted on atrailer and powered by a hydraulic system. The device is intended to bepulled by a tractor around a field, and the motion of one of the vehiclewheels activates a piston and cam-drive arrangement in communicationwith the soil sampler's hydraulics. Since the sampling periodicity isdriven by the motion of one of the wheels on the trailer, the deviceautomatically samples soil at regular intervals, regardless of the speedof the tractor pulling the trailer. The device uses a sampling tube thatis forced into the ground for sample collection. Since the device doesnot stop in order for samples to be taken, the sampling tube is designedto pivot upon entry into the ground. The sampling tube is returned toits original insertion position (angled toward the front of the trailer)by means of a spring.

U.S. Pat. No. 3,625,296 to Mabry et al. teaches another soil samplingdevice that is mounted on a trailer, and which is intended toperiodically sample soil over which the trailer passes. A digger foot isused to collect the soil sample, the foot being mounted at the end of alever that includes a cam follower at its opposite end. By means of thecam follower, a cam on one of the tractor's wheels forces the diggerfoot into the ground as the trailer travels, thereby scooping a soilsample. As the cam rolls forward, the digger foot is released and aspring biases the digger foot upward, where it strikes a bumper blockand deposits the soil sample into a collection container. Like theAlexander device, the Mabry et al. device automatically samples soil atregular intervals, since its sampling periodicity is driven by thedistance traveled by the cam-equipped tractor wheel.

U.S. Pat. No. 5,741,983 to Skotnikov et al. teaches a thirdtrailer-mounted automatic soil sampling device. In this case, anodometer is used to monitor the distance of travel of the trailer, whichdrives the sampling period of the device. The device utilizes ashaft-drive and linkage arrangement to control the period of thesampling action based upon the rotation of one of the trailer's wheels.A complex linkage arrangement allows the sampling tube to be raised intoa position to eject and deposit a sample during each sampling cycle. Thedevice further includes a bagging mechanism, whereby each of the samplesthat are drawn from the ground may be automatically bagged and labeledfor later laboratory analysis.

The automatic sampling mechanisms described above suffer from importantdisadvantages. Mechanisms that simple scoop a sample of material fromthe top of the ground are undesirable since such a sample may not berepresentative of the lower levels of the soil in the area that issampled. The most relevant section of the soil is that section that willbe in greatest contact with the roots of the crop to be planted, whichin the case of almost all crops will be soil that lies at some distancebelow the surface. Further, in many applications the most desirablesample will be one that spans a section of the soil, from the surface toa pre-determined depth beneath the surface. A scooping mechanism willlikely be unable to probe deeply enough to produce a sufficient sampleto meet this need.

Although sampling mechanisms that insert a tube into the ground tocollect a sample are superior to scoop mechanisms in many applications,the tube-type sampling mechanisms known in the art also suffer fromdisadvantages. It is desirable in an automatic sampling mechanism thatthe sample be taken without requiring the vehicle that is carrying thesampling mechanism to stop. This greatly simplifies the task of theoperator of the vehicle, since sampling can be automatically performedas the operator follows a pre-determined course over a field ofinterest, and also because it will save the operator a significantamount of time during the sampling process. The process of inserting andremoving a tube from a moving vehicle, however, presents a number ofdifficulties. In one case these difficulties have been addressed by theuse of a tube that pivots, thereby allowing the tube to be inserted intothe ground at a forward-sloped angle, while it pivots rearwardly untilthe tube is removed. Depending upon the hardness of the soil, however,this may create a great deal of stress upon the tube. The pivotingaction causes the tube to push backward against soil that is rearward ofthe tube at its distal end, and push forward against soil that isforward of the tube at its proximal end. While this may be a workablesolution in very loose, highly compressible soil, this will likely leadto bending, excessive wear, or other damage to the tube in more firmlypacked soil, or soil that may contain rocks or other hard obstacles.

Another solution to the problem of vehicle motion while the tube isinserted in the ground is a complex linkage arrangement that allows thestructure immediately supporting the sampling tube to “follow” the tubeduring the portion of the sampling cycle when the tube is inserted intothe ground. While this arrangement may avoid the problems presented bytube rotation, the structure and linkages necessary for thisfunctionality are complex, and would likely be expensive to manufactureand difficult to maintain.

Another disadvantage of the systems described above is that they do nottake advantage of the efficiencies that may be achieved with the use ofGPS information during sampling. Mapping of a field of interest, andselection of areas within the field for individual analysis, is greatlysimplified using GPS information, and furthers the goal of making theprocess as transparent and automatic for the operator as possible.

What is desired is an automatic soil sampling mechanism that facilitatesthe sampling of soil across an area of interest by simply tracing themechanism over the area, while also being inexpensive to manufacture andsimple to maintain, and taking advantage of GPS information. Thelimitations of the prior art are overcome by the present invention asdescribed below.

DISCLOSURE OF INVENTION

The present invention is directed to an automatic soil samplingapparatus that comprises a sampling assembly that revolves around acontinuous track while the apparatus is in motion. The mechanism may bemounted on a trailer or other like vehicle. The drive mechanism for thesampling assembly is powered by the movement of the vehicle as the trackmaintains contact with the ground. The sampling assembly revolves withthe continuous track of the drive mechanism, allowing it to retrievesoil samples as it passes over the ground during each revolution. Sincethe drive mechanism is powered by the vehicle's motion with respect tothe ground, the sampling assembly will in effect be stationary withrespect to the ground as it is passing along that portion of thecontinuous track's path that is in contact with the ground. Thus thesampling tube of the sampling assembly may be inserted into the groundand removed while passing along the bottom portion of the drive withoutthe need for a pivoting action or complex linkages in order to hold thetube in a particular position while the sample is collected. A rail orguide arrangement, against which the sampling assembly rides, may beused to extend and retract the sampling tube, while also extending andretracting an ejector bar within the sampling tube in order to removethe sample from the sampling tube.

Soil cores ejected from the sampling tube fall into a collection tray,which in certain embodiments may include a wire grid to break the sampleinto smaller portions, and an auger system to direct soil into adelivery tube beneath the tray. A pneumatic delivery system may be usedin certain embodiments to move collected samples from the collectiontray to sample storage containers, which may be located adjacent theoperator of a vehicle pulling the sampling mechanism for ease of access.A rotating tray with multiple storage containers may be employed incertain embodiments in order to collect samples. A computer-based GPSmapping system may be used in conjunction with the present invention inorder to coordinate the mapping of a field of interest and collection ofsamples at appropriate locations.

It is therefore an object of the present invention to provide for a soilsampling mechanism that may automatically collect soil samples over anarea of interest.

It is a further object of the present invention to provide for a soilsampling mechanism that provides sampling tubes that are stationary withrespect to the ground during a portion of the sampling cycle so that thetube may be easily inserted and retracted from the ground in order tocollect samples.

It is also an object of the present invention to provide for a soilsampling mechanism that is inexpensive to produce and easy to maintain.

It is also an object of the present invention to provide for a soilsampling mechanism that allows for the pneumatic movement of collectedsamples from a collection tray to a location more convenient to anoperator.

It is also an object of the present invention to provide for a soilsampling mechanism that allows the automatic collection of a number ofsoil samples in a plurality of containers on a rotating tray for ease ofanalysis.

It is also an object of the present invention to provide for a soilsampling mechanism that allows for the use of a computer-based mappingsystem in order to map an area of interest and collect samples from theappropriate portions of the area of interest.

These and other features, objects and advantages of the presentinvention will become better understood from a consideration of thefollowing detailed description of the preferred embodiments and appendedclaims in conjunction with the drawings as described following:

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a side elevational view of a preferred embodiment of thepresent invention including a tow vehicle.

FIG. 2 is a side elevational view of the drive components of a preferredembodiment of the present invention.

FIG. 3 is a top plan view of a preferred embodiment of the presentinvention.

FIG. 4 is a side elevational view of a preferred embodiment of thepresent invention, in partial cut-away along line Z-Z of FIG. 3.

FIG. 5 is a perspective view of the sampler assembly track componentsfrom a preferred embodiment of the present invention.

FIG. 6 is a side elevational view of the sampler assembly trackcomponents from a preferred embodiment of the present invention.

FIG. 7 is a side elevational view of a sampler assembly from a preferredembodiment of the present invention.

FIG. 8 is a perspective view of a sampler assembly from a preferredembodiment of the present invention.

FIG. 9 is a top plan view of a soil collection hopper assembly accordingto a preferred embodiment of the present invention.

FIG. 10 is a side elevational view of a soil collection hopper assemblyaccording to a preferred embodiment of the present invention, in partialcut-away along line A-A of FIG. 9.

FIG. 11 is an end elevational view of a soil collection hopper assemblyaccording to a preferred embodiment of the present invention, in partialcut-away along line B-B of FIG. 9.

FIG. 12 is a progressive view of the motion of a sampling probe of apreferred embodiment of the present invention during the soil probecycle.

FIG. 13 is a progressive view of the motion of a sampling probe of apreferred embodiment of the present invention during the soil ejectionand return cycle.

FIG. 14 is a progressive view of the motion of a sampling probe in thebypass position according to a preferred embodiment of the presentinvention.

FIG. 15 is a progressive view of the motion of a sampling probe in theprobe position according to a preferred embodiment of the presentinvention.

FIG. 16 is a plan elevational view, in partial cut-away, of the samplecollection system according to a preferred embodiment of the presentinvention.

FIG. 17 is a plan elevational view of the sample collection systemaccording to a preferred embodiment of the present invention, in partialcut-away along line A-A of FIG. 16.

FIG. 18 is a plan elevational view of the sample collection systemaccording to a preferred embodiment of the present invention, in partialcut-away along line B-B of FIG. 16.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to FIGS. 1-4, the preferred embodiment of the presentinvention may be described. The support structure of the preferredembodiment is provided by a trailer 10, which may include a U-shapedframe 12, a tongue 14, and support wheels 16. These components providesupport for drive mechanism 17. In the preferred embodiment, wheels 16are standard automobile wheels with rubber tires, but various otherforms of wheels 16 may be employed such that trailer 10 may be easilypulled across cultivated soil as well as ferried to and from the fieldalong paved or unpaved roads. Tongue 14 may be hitched to an all-terrainvehicle (ATV), tractor, or other powered vehicle 13 for the movement ofthe preferred embodiment in the field or other region where sampling isdesired. Although the preferred embodiment of the invention is notpowered, and thus relies on vehicle 13 for movement, alternativeembodiments might include any form of drive mechanism 17 that isintegrated with the other components of the invention, such that noseparate vehicle 13 is required.

Attached to U-shaped frame 12 is drive mechanism support frame 18. Drivemechanism support frame 18 preferably comprises two longitudinallyarranged bars on either side of the drive mechanism of the device, butany alternative arrangement that provides support from U-shaped frame 12to the drive mechanism may be used. Support frame 18 is attached toU-shaped frame 12 at attachment blocks 20 such that the drive mechanism17 may be raised or lowered with respect to U-shaped frame 12. Theraising of drive mechanism 17 is accomplished by the inflation of airstroke cylinders 22. Air stroke cylinders 22 ride against a structuralcomponent of U-shaped frame 12 and beneath the upper longitudinal armsof support frame 18. Filling air stroke cylinders 22 with air causes theupper longitudinal arms of support frame 18 to rise, thereby raisingdrive mechanism 17 off of the ground. In this manner, the device may betransported without the operation of the sampling mechanism, such aswhen the device is being moved to or from a field for sampling, ferryingbetween fields, or when turning a corner at the end of a sampling row.Air to fill air stroke cylinders 22 is maintained in air tanks 23, whichare filled by air compressor 24 through an air line (not shown forclarity). In the preferred embodiment, air compressor 24 is powered by a12-volt automotive battery (not shown), which may be mounted at anyconvenient location on trailer 10, such as above tongue 14. The chargein the battery is maintained through the operation of alternator 40. Inalternative embodiments of the invention, air stroke cylinders 22 may bereplaced by other means for raising and lowering drive mechanism 17,such as lineal actuators or hydraulic cylinders.

Support frame 18 connects to drive mechanism 17 through lower framemembers 26 and upper frame members 28. The two front idler wheels 29 aredisposed between the forward ends of lower frame members 26 and upperframe members 28. Each of front idler wheels 29 ride on a flange-mountroller bearing attached at the forward ends of each of lower framemembers 26, and are connected by a common axle (not shown). Alsoattached at each of lower frame members 26 are ground wheels 30. Likefront idler wheels 29, ground wheels 30 are mounted on roller bearings.In the preferred embodiment, a total of five ground wheels 30 areemployed on each side of drive mechanism 17. Sandwiched between the rearends of upper frame members 28 are rear idler wheels 31. Like frontidler wheels 29, rear idler wheels 31 rides on an bearings with nocentral axle; in the case of rear idler wheels 31, the bearings aremounted at the rearward ends of upper frame members 28. It may be notedthat in alternative embodiments of the invention, various numbers ofidler wheels and ground wheels may be employed. The key considerationsare that sufficient support for drive mechanism 17 must be provided, andsufficient space must be maintained in the interior of drive mechanism17 for the cycling of the sampling equipment as described hereafter. Byway of example, one possible alternative embodiment would involve fourwheels set in a roughly rectangular arrangement, with the omission ofthe ground wheels. Many other configurations are possible within thescope of the present invention.

Rotating around front idler wheels 29, ground wheels 30, and rear idlerwheels 31 is track 32. Track 32 is preferably constructed of rubber, andincludes tread or cleats on the exterior in order to engage the groundwithout significant slippage during operation. To the interior of track32 are alignment lugs that are positioned to either side of each offront idler wheels 29 and rear idler wheels 31 during rotation, suchthat track 32 is engaged with front idler wheels 29 and rear idlerwheels 31, and the revolution of track 32 will cause these wheels toturn and prevent slippage of track 32 from front idler wheels 29 andrear idler wheels 31. As will be apparent from this description, thelowering of drive mechanism 17 by the release of pressurized air fromair stroke cylinders 22 will cause track 32 to make firm contact withthe ground. The weight of drive mechanism 17 will cause the tractionelements of track 32 to engage the ground when trailer 10 is beingpulled, and thus cause track 32 to rotate around front idler wheels 29,ground wheels 30, and rear idler wheels 31. The speed of track 32 duringrotation will precisely match the ground speed of trailer 10, providedno significant slippage between the ground and track 32 occurs. Therotation of track 32 about the idler wheels and ground wheels of thepreferred embodiment should be sufficiently free that no slippage occursbetween track 32 and front idler wheels 29 and rear idler wheels 31. Ifdrive mechanism 17 is raised by the inflation of air stroke cylinders22, then track 32 will cease to revolve since it is no longer in contactwith the ground.

As shown in FIG. 2, turnbuckle adjustment 33 provides adjustablepressure to hold apart lower frame members 26 and upper frame members28, thereby maintaining the proper tension on track 32. Proper tensionis necessary to ensure that track 32 properly tracks during rotationwith respect to front idler wheels 29 and rear idler wheels 31.

It may be noted that as track 32 passes front idler wheels 29 and passesunder ground wheels 30, any given location on track 32 that is incontact with the ground maintains contact with the same section ofground until it again rises into the air toward the last ground wheel30. This is an inherent property of any drive arrangement employing atrack revolving around a plurality of sprockets or wheels. The inventiontakes advantage of this characteristic since the insertion andretraction of a sampler that follows track 32 may be performed withoutmovement of the sampler with respect to the ground, as will be describedhereafter.

While in the preferred embodiment the ground engagement of the inventionis provided by rubber track 32, many other engagement means may beemployed in alternative embodiments. Metal tracks could be employed,which are commercially available. Another embodiment may feature a pairof roller chains that rotate about sprocket pairs, with cross piecesfitted between the roller chains forming in effect a track-typearrangement. Channel iron in a “C” shape may be ideal for thisembodiment since the rides forming the arms of the “C” shape may befaced outwardly in order to provide traction for drive mechanism 17. Inanother alternative embodiment, track 32 may be replaced simply withwheels that contact the ground and transfer their rotational energy,through mechanical linkages or otherwise, to a set of sprockets orwheels that drive the revolution of the sampling mechanism. In yetanother alternative embodiment, a powered drive system may be employed,such that the sampling mechanism rotates under power from a motor,engine, or the like, and no direct contact between the ground and anydrive mechanism is in fact required.

Also mounted at one of upper frame members 28 is rotary vane compressor38. Compressors of the rotary vane type are well known in the art andwidely available commercially. Compressor 38 is connected to soilejection hopper assembly 34 by an air line (not shown for clarity), theoperation of which is described hereafter. Compressor 38 is powered byone of rear idler wheels 31 through an idler belt (not shown forclarity). Two idler belts are employed in the preferred embodiment, onecorresponding to each rear idler wheel 31, with each of the idler beltssandwiched between rear idler wheels 31 and track 32. In the case of theidler belt on the same side of drive mechanism 17 as compressor 38, theidler belt engages gearbox 44, which affects a step-up of rotationalspeed from rear idler wheel 31. In the preferred embodiment, a gearbox44 with a step-up ratio of about 3.5 to 1 is employed. This providessufficient rotational velocity to drive compressor 38. The gearbox thendrives compressor 38 by means of compressor belt 46. On the oppositeside of drive mechanism 17, the other idler belt revolves around theopposite rear idler wheel 31 and engages an inner sheave (not visible inFIG. 3) on jackshaft 48: Because of the different sheave sizes onjackshaft 48, a step-up in rotational speed is achieved; a step-up ratioof about 3 to 1 is employed in the preferred embodiment. Alternator 40is thus driven from jackshaft 48 by alternator belt 50. As a result ofthis arrangement, whenever drive mechanism 17 is lowered and track 32 isturning, compressed air will be reaching soil ejection hopper assembly34 from rotary vane compressor 38, and alternator 50 will be chargingthe battery of the device.

Referring now in particular to FIGS. 5-8, the structure of a preferredembodiment of a sampler assembly 60 according to the invention may bedescribed. Sampler base 62 is preferably formed of two steel plates thatare spaced slightly apart. Sampler base 62 is attached to track 32 atbase hinge 64. Base hinge 64 allows sampler assembly 60 to pivot withrespect to track 32 during operation. Base hinge 64 is attached to track32 by means of base bolts 65, which pass through track 32 engaging basehinge 64 on one side and base hinge plate 67 on the other. Track 32 isthus sandwiched between base hinge 64 and base hinge plate 67. As aresult of this attachment, sampler assembly 60 rotates with track 32 astrack 32 turns around front idler wheels 29 and rear idler wheels 31,with sampler assembly 60 remaining between each pair of wheels duringthis process, and further allowing sampler assembly 60 to pivot withrespect to track 32 in order to negotiate all necessary turns duringrevolution.

Probe 66 is positioned perpendicularly to sampler base 62, such that itis extendible between the plates forming sampler base 62. Probe 66 rideson rollers 69; in the preferred embodiment there are four rollers 69sandwiched between the sides of sampler base 62 (one roller 69 isvisible in FIG. 8). Rollers 69 ride on pins that connect between thesides of sampler base 62. Rollers 69 function to guide probe 66 as itpasses between the sides of sampler base 62. Probe 66 is thus preventedfrom rocking backward or forward with respect to sampler base 62 by fourrollers 69.

The point at which sampler assembly 60 is attached to track 32 featuresan aperture that is sized to receive probe 66. As a result, probe 66 isextendible through track 32 in order to probe into the soil in a mannerthat will be described in greater detail hereafter. In the preferredembodiment, probe 66 is constructed from square stainless steel tubingthat is about 1.27 cm in width. Stainless steel is preferred in order toreduce the likelihood of corrosion on probe 66, which may affect theperformance of the device. The tubing is preferably annealed foradditional strength. Many other configurations may be used inalternative embodiments, including round steel tubing, but square tubingwas chosen in the preferred embodiment for ease of manufacture andmaintenance.

Slideably fitted within probe 66 is ejector 68. Ejector 68 is moveablefrom a position where it retracts outwardly from the end of probe 66such that it is almost entirely outside of probe 66, to a point where itextends through the full length of probe 66. Ejector 68 is preferablyformed of square stainless steel rod that is about 0.79 cm in width. Therod is preferably annealed for additional strength. Many otherconfigurations are possible, with ejector 68 preferably fitting snuglywithin probe 66 but not so tightly that its freedom of movement withinprobe 66 is significantly limited by friction. Ejector 68 may, in thepreferred embodiment, include a wiper (not shown) attached to the distalend of ejector 68, which extends into and through probe 66. In apreferred embodiment, the wiper may be formed of ultrahigh molecularweight (UHMW) polyethylene, or a similar soft and durable material. Thepurpose of the wiper is to ensure that all sample material within probe66 is ejected when ejector 68 passes through probe 66, without allowingsoil or other debris to be trapped between the inner wall of ejector 68and probe 66.

Scissor frame assembly 70 supports probe 66 and ejector 68 in positionwith respect to sampler base 62. In the preferred embodiment, scissorframe assembly 70 may be constructed from individual annealed stainlesssteel links that are similar to steel roller chain but with increasedpitch. The links are pinned, bolted, or otherwise attached, preferablyusing roller chain pins, bushings, and rollers, in such a manner as toform a collapsing double-scissor arrangement as shown in FIGS. 7 and 8.Scissor frame assembly 70 is attached to sampler base 62 by pins orother means. Scissor frame assembly 70 is attached at or near theproximal end of probe 66 at lower link point 72, and is attached at ornear the proximal end of ejector 68 at upper link point 74. Theseconnections are preferably bolted or otherwise attached in a manner toallow rotation, since the individual link components of scissor frameassembly 70 must pivot with respect to probe 66, ejector 68, and base 62as scissor frame assembly 70 compresses and expands. In the preferredembodiment, scissor frame assembly 70 may be biased by internal springs(not shown) to assume a collapsed shape, whereby probe 66 extendsthrough sampler base 62 and ejector 68 extends fully into probe 66.

Attached at lower link point 72 of scissor frame assembly 70 are a pairof probe guide wheels 76. Probe guide wheels 76 are attached to eitherside of probe 66 and hingeably linked to scissor frame assembly 70 atlower link point 72. Probe guide wheels 76 thus travel up and down withprobe 66 as the lower portion of scissor frame assembly 70 compressesand expands. Probe guide wheels 76 preferably travel on ball bearings,and may rotate freely. Likewise, attached at upper link point 74 ofscissor frame assembly 70 are a pair of ejector guide wheels 78. Ejectorguide wheels 78 are attached to either side of ejector 68 and hingeablylinked to scissor frame assembly 70 at upper link point 74. Ejectorguide wheels 78 thus travel up and down with ejector 68 as the upperportion of scissor frame assembly 70 compresses and expands. Like probeguide wheels 76, ejector guide wheels 78 preferably travel on ballbearings, and may rotate freely. Probe guide wheels 76 and ejector guidewheels 78 function as followers to manipulate sampler assembly 60 in amanner that will be described hereafter. It will be seen, however, thatas a result of this arrangement of sampler assembly 60, the applicationof upward pressure on probe guide wheels 76 will cause probe 66 toretract against the bias of the springs of the lower section of scissorframe assembly 70. Likewise, it will be seen that the application ofupward pressure on ejector guide wheels 78 will cause ejector 68 toretract from within probe 66 against the bias of the springs of theupper section of scissor frame assembly 70. Alternative embodiments mayinclude various other types of followers, including sliding followersrather than the rotating followers implemented in the form of probeguide wheels 76 and ejector guide wheels 78.

In addition to probe guide wheels 76 and ejector guide wheels 78,sampler assembly 60 preferably includes two additional pairs of wheelsin the form of base guide wheels 80. Like probe guide wheels 76 andejector guide wheels 78, base guide wheels 80 are mounted on ballbearings or otherwise such that they may freely rotate. The purpose ofbase guide wheels 80 is to hold sampler assembly 60 in position as itrotates with track 32 in a manner as will be described hereafter.

Also attached to sampler base 62 for purposes of holding samplerassembly 60 in position as it rotates is strut 79. Strut 79 ispreferably formed from steel rod, and features a threaded proximal endto receive a nut. Strut 79 is connected between the sides of samplerbase 62 through a pivoting block (not shown) that is pinned between thesides of sampler base 62. Strut 79 is inserted through an aperture inthis block such that strut 79 may freely slide longitudinally withinthis block. The nut on the proximal, threaded end of strut 79 stops thetravel of strut 79 within this block at the proximal end. Strut 79 ispinned to track 32 at its distal end by the insertion of a pin (notshown) through track 32 and connector 81. In alternative embodiments,strut 79 may be fastened to track 32 by any other secure means. As aresult of this arrangement, sampler assembly 60 may rock forward andbackward with a limited degree of freedom, thereby allowing samplerassembly 60 sufficient freedom of movement that sampler assembly 60 maynegotiate the turns at the idler wheels of drive mechanism 17 withoutdamage to sampler assembly 60.

Referring now to FIGS. 9-11, the construction of hopper assembly 34according to a preferred embodiment of the present invention may bedescribed. Hopper bracket 82 provides support for a pair of hopper wheelframes 86. Four hopper wheels 84 are mounted to each of the two hopperwheel frames 86 such that hopper wheels 84 ride against track 32. Hopperwheels 84 are mounted on ball bearings or otherwise in order to allowthem to rotate freely as track 32 passes underneath.

Also mounted to hopper bracket 82 but beneath track 32 is hopper 88.Hopper 88 is preferably formed as an elongated, U-shaped trough, alignedlongitudinally with and at the center of track 32, with an open top toreceive soil. It will be seen that as probe 66 revolves with track 32,it will pass over the full length of hopper 88. Soil from probe 66 maythus be deposited in hopper 88 through the aperture in track 32 beneathprobe 66 as probe 66 passes over hopper 88 in a manner as will bedescribed hereafter.

Referring specifically now to FIG. 9, soil slicing wires 98 are disposedabove the open top of hopper 88, and held in appropriate tension bytensioning springs 100. As soil is deposited into hopper 88 as hopper 88is passed over by probe 66, the soil will be tightly packed and mightcause hopper 88 to clog. The purpose of slicing wires 98 is to break upthe soil into smaller chunks before reaching the bottom of hopper 88.While soil slicing wires 98 and tensioning springs 100 form a part ofthe preferred embodiment of the invention, these elements may be omittedfrom alternative embodiments of the invention if soil conditions do notwarrant their use.

Referring again to each of FIGS. 9-11, disposed within and along thelength of hopper 88 is auger 90. Auger 90 is sized to fit snugly withinthe U-shaped trough formed by hopper 88. The blade portion of auger 90is formed in a clockwise rotational direction over one half of hopper88, and is formed in a counter-clockwise rotational direction over theother half of hopper 88. The directions of rotation are chosen such thatas auger 90 rotates within hopper 88, any soil that is deposited ineither end of hopper 88 will be drawn to the center. Auger pulley 92 isused to drive the rotation of auger 90 by a belt (not shown) asexplained hereafter.

Disposed beneath auger 90 at a cut-out in the base of hopper 88 isspider wheel 94. The vanes of spider wheel 94 are formed such that as itrotates within its housing 96, soil that collects in the center portionof hopper 88 is drawn downward into housing 96. The vanes of spiderwheel 94 form an air lock arrangement analogous to a revolving door,such that soil that is in the bottom portion of housing 96 iseffectively sealed off from soil in hopper 88 above. The soil in thebottom portion of housing 96 may thus be pneumatically removed in acontinuous fashion during operation.

Referring now to FIG. 11, compressed air is provided to housing 96 bymeans of air inlet 102. Air passing from inlet 102 to housing 96 forcessoil that has collected in housing 96 by means of the rotation of spiderwheel 94 to exit through air outlet 104. This soil is driven by means ofair pressure to a collection point as described hereafter. Thecompressed air that passes into inlet 102 is received from rotary vanecompressor 38, through an attached air hose (not shown).

Spider wheel 94 is mounted on a shaft as shown in FIG. 11, and driven bya flexible drive shaft (not shown) that is connected to a stub extendingfrom a rear idler wheel 31. Drive pulley 106 on the spider wheel driveshaft drives auger pulley 92, as shown in FIG. 10, using two idlers (notshown) to turn the drive belt ninety degrees.

Referring again to FIGS. 5 and 6, the construction of guide assembly 108according to a preferred embodiment of the invention may be described.The purpose of guide assembly 108 is to lead sampler assembly 60 alongprecise pathways as it travels with track 32, lowering and raising probe66 and ejector 68 by means of manipulating the position of probe guidewheels 76 and ejector guide wheels 78 with respect to track 32. Inaddition, guide assembly 108 serves to securely hold sampler assembly 60in position at certain key points as it revolves with track 32 byproviding a track for base guide wheels 80. As a result, guide assembly108 causes probe 66 and ejector 68 to automatically perform theirintended functions at precise points along the rotation of samplerassembly 60 around track 32. In the preferred embodiment, guide assembly108 is comprised of two sets of tracks, one disposed to the left side ofdrive mechanism 17 and the other to the right side of drive mechanism17, such that each set of tracks provides support for the appropriatemember of each pair of probe guide wheels 76, ejector guide wheels 78,and base guide wheels 80 on the corresponding side of sampler assembly60. This arrangement is most clearly shown in FIG. 6. The space betweenthese corresponding pairs of tracks must be open to allow samplerassembly 60 to pass therebetween. Further in the preferred embodiment,each set of tracks comprises a pair of lower base tracks 110, upper basetracks 112, lower probe tracks 114, upper probe tracks 116, lowerejector tracks 118, and upper ejector tracks 120. Each of these tracksmay be attached to structural elements of drive mechanism 17 and therebyheld rigidly in place as appropriate.

It should be noted that in the preferred embodiment, the various guideplates need not extend around the entire path of sampler assembly 60.Instead, guide plates are only needed at the points where alignment ofsampler assembly 60 is critical, or where probe 66 or ejector 68 must beextended or retracted. Numerous other arrangements of guide plates couldbe employed in alternative embodiments, including a different number ofguide plates, either more or less than the number used in the preferredembodiment. In addition, other forms of guide assembly 108 may beemployed other than tracks, including without limitation in onealternative embodiment pairs of walled channels that trap one or more ofprobe guide wheels 76, ejector guide wheels 78, and base guide wheels 80along part of or along the entire path followed by sampler assembly 60as it follows track 32.

Referring now to FIGS. 12 and 13, the cycle by which soil sampling isperformed as trailer 10 is moved across the ground according to apreferred embodiment of the present invention may now be described. Atstep A of FIG. 12, sampler assembly 60 has just revolved around frontidler wheels 29. Because base guide wheels 80 are sandwiched betweenlower base track 110 and upper base track 112, base guide wheels 80 holdsampler assembly 60 rigidly in place, with the proper alignment of probe66 toward the ground. It may be noted that in the preferred embodimentthis alignment is near the vertical but angled slightly forward at about12 degrees; in this way, probe 66 is perpendicular to track 32 at thepoint where probe 66 enters the ground, thereby minimizing the stressforces on probe 66 during insertion into the ground. Other alignmentsare, however, possible in alternative embodiments. It may further beseen that probe 66 is maintained in the fully retracted position, sincelower probe track 114 and upper probe track 116 are holding probe guidewheels 76 at a relatively large distance from sampler base 62. Ejector68 is collapsed fully within probe 66 at step A, because lower ejectortrack 118 is positioned so as to keep ejector guide wheels 80 relativelylow with respect to sampler base 62. Thus in step A, scissor frameassembly is compressed at its upper section, but is extended in itslower section.

Moving now to step B of FIG. 12, it may be seen how the position ofsampler assembly 60 changes as it continues its movement around the pathof track 32. Lower base track 110 and upper base track 112 continue tohold sampler base 62 rigidly in place, maintaining the proper angle ofprobe 66 with respect to the ground. As sampler assembly 60 moves fromstep A to step B, however, lower probe track 114 and upper probe track116 approach rubber track 32. As a result, probe guide wheels 65 arebrought toward sampler base 62, the lower portion of scissor frameassembly 70 is compressed, and probe 66 extends into the ground.Simultaneously, since lower ejector track 118 is not approaching theground, the distance between lower ejector track 118 on the one hand,and lower probe track 114 and upper probe track 116 on the other, isincreasing. Thus ejector 68 is gradually retracted from within probe 66,and the upper portion of scissor frame assembly 70 is extended. The factthat ejector 68 withdraws from probe 66 as probe 66 is inserted into theground allows soil to enter probe 66 through its open distal end. Atstep B of FIG. 12, probe 66 is fully extended into the soil, and ejector68 is fully retracted from within probe 66. It may be noted that sincetrack 32 is moving at precisely the speed of trailer 10 (because track32 is driven by the motion of trailer 10 over the ground), the positionof probe 66 with respect to the ground does not actually change duringthe movement from step A to step B. Thus probe 66 may be inserteddirectly into the ground as illustrated without lateral stress beingexerted upon probe 66 by the soil immediately surrounding the point ofinsertion.

Moving now to step C of FIG. 12, it may be seen that lower base track110 and upper base track 112 continue to hold sampler base 62 rigidly inplace through the action of base guide wheels 80, maintaining the properangle of probe 66 with respect to the ground. As sampler assembly 60moves from step B to step C, however, lower probe track 114 begins tomove upward and away from rubber track 32. As a result, probe guidewheels 65 are carried away from sampler base 62, the lower portion ofscissor frame assembly 70 is extended, and probe 66 is retracted fromthe ground. Since lower ejector track 118 maintains an even distancewith lower probe track 114 during the progression from step B to step C,ejector 68 maintains its fully withdrawn position with respect to probe66. At step C of FIG. 12, probe 66 is fully retracted from the soil, andejector 68 remains fully withdrawn from within probe 66. The friction ofsoil within probe 66 causes the soil to remain within probe 66, andsince ejector 68 maintains its fully withdrawn position, there is noforce acting to eject the soil from within probe 66.

Turning now to step D of FIG. 13, it may be seen that the distal end ofprobe 66 has now reached the lower end of hopper 88. Lower base track110 and upper base track 112 continue to hold sampler base 62 in place,with the proper alignment of probe 66 maintained, as a result of baseguide wheels 80. During the movement from step D to step E of FIG. 13,lower probe track 114 continues to rise while lower ejector track 118assumes a flat trajectory. Also, the side of lower ejector track 118above ejector guide wheels 78 is now so close to ejector guide wheels 78that it may engage them from the top side, creating a narrow channel forejector guide wheels 78. As a result, ejector guide wheels 78 begins toapproach sampler base 62, the upper portion of scissor frame assembly 70becomes compressed, and ejector 68 begins to compress within probe 66.At step E of FIG. 13, ejector 68 is fully extended with in probe 66. Theresult of this progression from step D to step E is that as probe 66passes over hopper 88, probe 66 remains retracted but ejector 68continuously pushes soil out from probe 66 into hopper 88. By the timestep E is reached, probe 66 is at the upper end of hopper 88, ejector 68is at full compression within probe 66, and all of the soil within probe66 has been deposited into hopper 88.

Turning now to step F of FIG. 13, it will be seen that lower probe track114 rapidly approaches 32 in the progression from step E to step F.Simultaneously, lower ejector track 118 maintains its close position tolower probe track 114, with ejector guide wheels 78 remaining trappedbetween the portion of lower ejector track 118 beneath them and theportion of lower ejector track 118 that curves above them. As a resultof these changes, probe 66 rapidly extends from sampler assembly 60,such that by the time step F is reached at the back of rear idler wheels31 probe 66 is fully extended through track 32. Both the lower and upperportions of scissor assembly 70 are now fully compressed, since probe 66is fully extended and ejector 68 is fully collapsed within probe 66.This position allows sampler assembly 60 to maneuver around therelatively tight turn at rear idler wheels 31. In addition, it will benoted that lower probe track 114 functions to hold sampler base 62 inthe proper position for this turn through contact with base guide wheels80. This position of sampler assembly 60 is maintained as samplerassembly 60 rotates to the position of step G of FIG. 13.

Turning now to step H of FIG. 13, it may be seen that lower probe track114 gradually slopes away from track 32. This causes probe guide wheels76 to be pulled away from sampler base 62, the lower portion of scissorframe assembly 70 extends, and probe 66 retracts within track 32. By thetime that sampler assembly 60 reaches step H, probe 66 is in the fullyretracted position. Since lower ejector track 118 also slopes away fromtrack 32, and maintains an even distance between itself and lower probetrack 114 between steps G and H, the position of ejector 68 with respectto sampler assembly 60 does not change. Thus the upper portion ofscissor frame assembly 70 remains compressed, and ejector 68 remainsfully compressed within probe 66.

Inertia due to the forward travel of rubber track 32 causes probeassembly 60 to hinge rearward; for this reason, strut 79 (shown in FIGS.7 and 8) functions to hold the position of probe assembly 60 withrespect to track 32 during parts of the probing cycle, particularly asprobe assembly 60 passes rear idler wheels 31. It may be noted thatthere is no support for base guide wheels 80 at the upper portion oftrack 32 as provided by lower base track 110 and upper base track 112 atthe lower portions of track 32; no such support is needed in thepreferred embodiment since the angle of probe 66 and the precisealignment of sampler base 62 is not as critical during this portion ofthe probing cycle. Finally, it may also be noted that upper ejectortrack 120 provides an upper bound for the movement of ejector guidewheels 78 during portions of this cycle.

Turning now to FIGS. 14-15, the operation of a sampling bypass mechanismaccording to a preferred embodiment of the present invention may bedescribed. It may occur that probe 66 strikes a rock or other hardobject during a sampling cycle, and in such case it would be desirableto prevent damage to probe 66 by skipping the sampling operation duringthat particular cycle and maintaining probe 66 in a retracted position.Likewise, when large plots of grounds are covered for sampling, it maybe desirable, for example, to sample only every second revolution ofprobe 66, third revolution of probe 66, or any other multiple of thenumber of revolutions. This may be accomplished through the manipulationof guide air cylinders 132. Guide air cylinders 132 are linked to therearward portion of lower probe track 114 and upper probe guideextension 128, which may rotate about pivot point 130. Extension of eachair cylinder 132, as shown in FIG. 15, allows the rearward portion oflower probe track 114 and upper probe guide extension 128 to pivotaround pivot point 130 downwardly into the normal operating position.Air pressure within air cylinder 132 holds this position during normalsampling. If, however, probe 66 strikes an object that createssufficient upward pressure on probe 66 to overcome the set air pressurein air cylinder 132, then air cylinder 132 may retract as shown in FIG.14. The result of this retraction is the movement of probe 66 from theground, and the sampling cycle will thereby be bypassed. In addition,air cylinder 132 may be retracted pneumatically for the purpose ofskipping cycling samples as part of normal operations. The retractionand extension of air cylinder 132 may preferably be controlled bycomputer when used as part of the normal sampling operation. Airpressure for the operation of air cylinder 132 is provided by air tanks23, shown in FIG. 4. Air from air tanks 23 is provided to air cylinder132 by an air line (not shown for clarity). Air tanks 23 are thus usedas a form of air bladder, allowing probe 66 to retract when anobstruction is encountered that is sufficiently resistive to the forceof probe 66 to overcome the air pressure within air tanks 23.

Turning now to FIG. 10, that portion of the preferred embodiment of theinvention that is concerned with sample collection may be described.Preferably, these components are located within reach of the operator,such as the driver of a tractor that is pulling trailer 10 duringoperation of the soil sampler. One possible arrangement is shown in FIG.1, with the components located forward of the operator's position onvehicle 13. Soil delivery line 122 is used to pneumatically deliver eachsoil core from soil ejection hopper assembly 34 to soil collectioncanisters 126. Soil collection canisters are disposed upon carousel 125.While any number of collection canisters 126 may be employed, eightcanisters are used in the preferred embodiment. The size of thesecanisters may vary, but in the preferred embodiment each canister 126 issized to hold a plurality of soil cores. The rotation of carousel 125 iscontrolled by an onboard computer (not shown) that is in communicationwith control panel 124. Alternatively, control panel 124 may be atouchscreen display. This rotation may be accomplished by means ofelectric tray motor 134, as in the preferred embodiment, or byhydraulic, pneumatic, or other means. Electric tray motor 134 causesdrive gear 136 to rotate, which in turn rotates secondary gear 138attached to carousel 125. By rotating carousel 125, soil arrivingthrough delivery line 122 may be deposited in any of canisters 126 asdesired. This process may be controlled automatically in the preferredembodiment according to the method as described hereafter. This processmay also be controlled, at the option of the operator, through a rotaryswitch positioned at control panel 124. Air exiting each canister 126 asair and soil arrive through delivery line 122 is filtered through afilter 140 attached to each canister 126; this prevents sample materialfrom being inadvertently blown out of canister 126, and further preventsdust from canister 126 from causing discomfort to the operator, who isin the preferred embodiment positioned closely adjacent to canister 126.

In a preferred method according to the present invention, a grower mayperform sampling over a field of interest utilizing mapping software andglobal positioning system (GPS) satellite information to highly automatethe sampling process. For example, consider a square field of interestthat of a size of 64 hectares. This field may be mapped using a GPSreceiver and mapping software, with a tractor that simple travels theperimeter of the field. Such software is commercially available fromcompanies such as Raven Industries of Sioux Falls, S. Dak., and TrimbleNavigation Limited of Sunnyvale, Calif. The field may then be dividedinto, for example, sixty-four sections from which unique samples will beanalyzed, using a grid that is overlaid by software onto the resultingfield map. Each of the sampling sections will thus be of a size of 1hectare.

In order to collect samples, the operator attaches trailer 10 to vehicle13 and pulls trailer 10 to the edge of the field of interest. It may benoted that drive mechanism 17 should be raised during transport to thefield of interest, since otherwise it will perform a sampling operationwhenever trailer 10 is in motion. Vehicle 13 is then used to pulltrailer 10 back and forth across the field, preferably crossing eachgrid section twice. Vehicle 13 may be manually guided by the operator,or the operator may take advantage of autosteer technology using GPSinformation, which is incorporated into many larger farm tractors nowproduced. Ground cores are periodically, and automatically, taken as thefield is traversed. The GPS receiver of the tractor constantly monitorsthe location of trailer 10, and the onboard computer may be programmedto send a signal to electric tray motor 134 as each grid line iscrossed. In this way, multiple cores are automatically taken from eachsampling section, while the cores are deposited in a correspondingcollection canister 126 without any further action by the operator. Inthe scenario described in the example hereof, it may be seen that sincethere are eight sampling sections of the field of interest in each row,and since there are eight canisters 126 on carousel 125, there is noneed to empty the canisters for further collection until an entire rowis completed. Preferably, carousel 125 and collection canisters 126 aredisposed adjacent the operator so that the canisters 126 can be emptiedinto labeled packages without the requirement of the operator movingfrom his position with respect to vehicle 13. Thus sampling may be acontinuous process over the entire field of interest, with samplingoccurring automatically while the operator may empty canisters, mixcollected samples if desired, and label the samples for later laboratoryanalysis. Alternatively, the system may include hardware to print alabel that corresponds to each sampling area to further automate thesampling process. The label may include a barcode for machine reading.When sampling is complete, the operator may raise drive mechanism 17with respect to tractor 10, and transport tractor 10 back to a storagearea.

It should be noted that while the size of a field of interest and asample area has been described with respect to the preferred embodiment,the invention may be employed in a field of any size, and sampling areasmay be either increased or decreased in size based on the accuracydesired and the time in which the operator has available to perform thesampling operation. As described above, once the sections of the fieldof interest increase to a certain size, it may be preferable to onlycollect cores on every second revolution of probe 66, every thirdrevolution of probe 66, or some other multiple of the number ofrevolutions. The inventor has found that roughly 100 cores are requiredto form a sample that has a mass of about 1 kg. Since the preferredsample size is around 0.25 kg, approximately 25 cores should be takenfor each sample when using the preferred embodiment of the invention.Canisters 126 should preferably be sized so that they can easily receiveat least this number of cores.

The present invention has been described with reference to certainpreferred and alternative embodiments that are intended to be exemplaryonly and not limiting to the full scope of the present invention as setforth in the appended claims.

1. A soil sampling apparatus, comprising: (a) a frame; (b) a rotationaldrive member mounted to said frame; (c) a probe carriage attached tosaid rotational drive member; (d) a probe extendibly attached to saidprobe carriage; (e) a probe follower linked to said probe; and (f) aguide comprising a probe follower track, wherein said probe followerrides within said probe follower track.
 2. The soil sampling apparatusof claim 1, wherein said probe follower track extends toward said drivemember from a first point on said guide toward a second point on saidguide, and said probe follower track extends away from said drive memberfrom said second point on said guide to a third point on said guide. 3.The soil sampling apparatus of claim 2, wherein said probe followertrack extends toward said drive member from said third point on saidguide to a fourth point on said guide.
 4. The soil sampling apparatus ofclaim 3, further comprising an ejector attached to said probe carriageand an ejector follower linked to said ejector, wherein said guidefurther comprises an ejector follower track, and wherein said ejectorfollower rides within said ejector follower track.
 5. The soil samplingapparatus of claim 4, wherein the distance between said probe followertrack and said ejector follower track increases from said first point onsaid guide to said second point on said guide.
 6. The soil samplingapparatus of claim 5, wherein the distance between said probe followertrack and said ejector follower track decreases from said third point onsaid guide to said fourth point on said guide.
 7. The soil samplingapparatus of claim 1, further comprising: (a) a sample collection traydisposed to receive a soil sample from said probe; (b) a samplecontainer; and (c) a pneumatic delivery system disposed between saidsample collection tray and said sample container.
 8. The soil samplingapparatus of claim 7, further comprising a sample tray in communicationwith said pneumatic delivery system, wherein said sample tray comprisesa plurality of sample containers.
 9. The soil sampling apparatus ofclaim 8, further comprising at least one auger at a base of saidcollection tray, and an air-lock delivery wheel beneath an aperture inthe base of said collection tray in communication with said pneumaticdelivery system.
 10. The soil sampling apparatus of claim 8, furthercomprising an electronic control system operable to deposit a sample inone of said plurality of sample containers based upon the location ofthe soil sampling apparatus with respect to a field of interest.
 11. Thesoil sampling apparatus of claim 10, wherein said electronic controlsystem comprises a GPS receiver.
 12. The soil sampling apparatus ofclaim 6, wherein said probe carriage comprises a first scissor memberconnecting said rotational drive member to said probe, and a secondscissor member connecting said ejector to said first scissor member. 13.The soil sampling apparatus of claim 6, further comprising a rotationalsection of said probe follower track, and a compressible cylinder incommunication with said rotational section of said probe follower trackwhereby said probe may be lifted by retraction of said compressiblecylinder.
 14. A machine for sampling soil, comprising: (a) a driveassembly comprising a track, a roller chain, or a belt, and furthercomprising a plurality of idler wheels or a plurality of sprockets; (b)a sampler assembly attached to said track, roller chain, or belt suchthat said sampler assembly rotates about said wheels or sprockets withsaid track, chain, or belt, said sampler assembly comprising a hollowprobe that is extendable with respect to said track, chain, or belt andan ejector that is extendable longitudinally within said hollow probe;(c) a sample collection bin disposed to receive a soil sample from saidhollow probe; and (d) a longitudinal guide in communication with saidsampler assembly, wherein said guide is operable to extend and retractsaid probe as said probe passes over the soil, thereby forcing saidprobe into and out of the soil, and wherein said guide is furtheroperable to extend said ejector longitudinally within said probe as saidprobe passes over said sample collection bin, thereby depositing asample into said sample collection bin.
 15. The machine of claim 14,wherein said guide is operable to retract said probe as said probepasses over said sample collection tray.
 16. The machine of claim 15,further comprising a sample container tray, wherein said samplecontainer tray comprises a plurality of sample containers, and saidsample tray is in communication with said sample collection bin.
 17. Themachine of claim 15, further comprising a probe follower and an ejectorfollower, and wherein said guide comprises a track to receive said probefollower along at least a portion of said guide and a track to receivesaid ejector follower along at least a portion of said guide.
 18. A soilsampler, comprising: (a) a frame; (b) a rotational drive assemblymounted to said frame, said rotational drive assembly comprising arotational drive member; (c) a hollow probe attached to said rotationaldrive member; and (d) a guide attached to said frame, wherein said guideis in communication with said probe whereby said probe is operable toextend and retract as said rotational drive member rotates with respectto said guide.
 19. The soil sampler of claim 18, further comprising anejector, wherein said ejector is in communication with said framewhereby said ejector is operable to extend within and retract fromwithin said hollow probe as said rotational drive member rotates withrespect to said guide.
 20. The soil sampler of claim 19, furthercomprising a compressible probe carriage that attaches said probe tosaid rotational drive member.
 21. The soil sampler of claim 20, furthercomprising a compressible ejector carriage that attaches said ejector toone of said rotational drive member and said probe carriage.
 22. Thesoil sampler of claim 21, further comprising a rotating probe followerattached to said probe and in rotational contact with said guide, and arotating ejector follower attached to said ejector and in rotationalcontact with said guide.
 23. A method for collecting soil samples usingan automatic soil sampling apparatus comprising an electronic controlsystem, said method comprising the steps of: (a) mapping a field ofinterest using GPS information; (b) dividing the field of interest intomultiple sample areas; (c) moving the automatic soil sampling apparatusover the field of interest such that at least one core is collected fromeach of the sample areas; and (d) depositing each of the cores into oneof a plurality of sample containers based upon the sample area in whichthe soil sampling apparatus occupies at a given time.
 24. The method ofclaim 23, wherein said electronic control system comprises a GPSreceiver, and the location of the soil sampling apparatus at a giventime is calculated based upon information received from the GPSreceiver.
 25. The method of claim 24, wherein multiple soil cores aretaken from each of the sample areas, and further comprising the step ofmixing cores taken from the same one of the sample areas in a samplecontainer.